Alloy steel



' To all whom it may concern:

UNITED STATES PATENT OFFICE.

ALLOY STEEL.

13,89,679. Io Drawing.

Be it known that I, PHILIP M. 'MOKESNNA, a citizen of the United States,residing at I Congress Heights, in the District of Columbia, haveinvented certain new and useful Improvements in Alloy Steel; and I dohereby declare the followm to be a full, clear, and exact description 0the same.

This invention relates to the steel industry and more especially to thatbranch of the industry havin g to do with alloy steels, the ob'ects ofthe invention being to produce an a 10y steel possessing the quahties oftoughness and resistance to breaka e by shock and at the same timehaving t e quality of red hardness, whereb it will be adapted for themanufacture o so-called high speed tools, etc. Heretofore steels usedfor lathe tools, milling cutters, hot dies, etc., hav been liable tobreakage under stress, as the steels heretofore available whilepossessing the quality of red hardness were deficient in strength.

The alloy steel of the'present invention will be best understood from ageneral statement of the ingredients and a specific statement of theanalysis of a characteristic sample. The alloy besides iron contains aeig teen per cent; a smaller per cent. of chromium, say, four per cent;carbon, say, sevemtenths of one percent, and tantalum two and one-halfper cent. The percentage of tungsten may vary from sixteen to twenty percent; chromium from two and one-half to five per cent; carbon fromsixty-hundredths to one and ten-hundredths per cent., and tantalum fromone'to three per cent. In addition to these elements, there may bepresent incidentally, sulfur, phosphorus, silicon, manganese, celumbium,vanadium, etc., which exist as impurities in the materials used andpersist in the product.

a A characteristic sample of the alloy steel or chemical analysis gavethe following percentages:

Tungsten 18. 40% Chromium 4.18% Tantalum 2. 00% Carbon. .78

Specification of Letters Patent.

large per cent. of tungsten, for example,

Patented Sept. 6, 1921.

Application filed April 2, 1021. Serial in. 458,081.

, Sulfur trace Phosphorus .0097 Silicon 40%- Manganese; 52% Columbium'.30%

J Vanadium 28% Remainder is iron.

The alloy has some remarkable advantages over ordinary red-hard steel.It hammered from the ingots without showing any cracks, while ordinaryred-hard steel cracks to more or less extent while being forged. Thegram, even of the cast structure, 'was fine in texture, and the alloycan be cast directly into mill ng cutters and other unforged tools WhlCare nonetheless strong and tough. Lathe cutting tests showed that thealloy was equal to the best high speed steel when made into tools forcuttin steel at high speed. Impact tests showed t at it was much morediflicult to break by a sudden straln.

The method of making this steel in an electric furnace as practised atthis timev is to melt first all the ingredients except the tantalum,allowing for a little extra tungsten which is used to carry the tantalumas shall be described. The molten bath hav- 1 n been obtained, quicktests should be ta en to see that the percentages of the elements in themolten alloy are such that when the tantalum (together with the smallamount of tungsten which is used to car 1t) is added, the content willbe within the llmits specified. Then a ferro alloy of tungsten andtantalum is added to the molten bath and the steel is poured after abouttwenty minutes.

The wa in which this ferro alloy of'tantalum an tungsten is preparedisto reduce together equal weights of wolframite and tantalite in anelectric furnace with carbon, or other reducing agent; or the reductionmay be made by the alumino thermic reaction; this results in a ferroalloy of tungsten and tantalum, the iron coming from the wolframite andtantalite mineral. The allo resulting is urified as set forth in my S.Patent 0. 1,208,596, processes of treating ferrctungs ell. Thecomminuted ferro-tungsten-tantalum, as purified by the 2% to 5 per cent.of chromium, and 1 to 3 above mentioned process, is used by throwpercent. of tantalum. in it into the molten bath of steel prefer- 2. A modeof producing steel alloy by 10 ab? in a thin sheet-iron can or contamer.adding to the molten steel bath a purified 5 at I claim is: alloy oftungsten, tantalum and iron.

1. An alloy steel of usual formula and containing 16 to 20 per cent. oftungsten, PHILIP M. MoKEN NA.

